Sofa



FIG. 1 is a front right perspective view of the sofa showing the new design;

FIG. 2 is a front left perspective view thereof;

FIG. 3 is a front view thereof;

FIG. 4 is a rear view thereof;

FIG. 5 is a bottom plan view thereof;

FIG. 6 is a top plan view thereof;

FIG. 7 is a right side view thereof; and,

FIG. 8 is a left side view thereof.

The dashed lines shown on the article represent topstitching. 

The ornamental design for a sofa, as shown and described. 